Certain parasiticidal pyrazole derivatives are already known. These include fipronil (5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethy lsulphinylpyrasole) and certain analogues thereof mentioned in International Patent Application WO 87/03781.
International Patent Application WO 92/13451 and EP 0 412 849 A2 describe, inter alia, 4-(imidazol-2-yl)pyrazoles with pesticidal activity.
U.S. Pat. No. 4,614,534 and EP 0 205 023 A2 describe various 1-phenylpyrazoles substituted by a non-fused aromatic heterocycle at the 4-position and H or alkyl at the 3-position, such compounds being useful as herbicides and/or plant growth regulators.
U.S. Pat. No. 4,740,231 describes various 1-aryl-5-alkoximinoalkylaminopyrazoles as herbicides and plant growth regulators. Brief mention is also made of the insecticidal activity of these compounds in this publication.
EP 0 418 845 A1 discloses various 1-phenylpyrazoles with heterocyclic and aryl substituents on the pyrazole, such compounds being useful as medicaments with antiinflammatory, analgesic and immune system activity. No 4-aryl- or 4-heteroaryl-substituted pyrazoles are specifically disclosed by this publication.